Say, you get a super-human chess AI, and a super-human accountant AI, and a super-human medical doctor AI, and a super-human material design AI, and a super-human lawyer AI, and… How many of these do you need in a bunch when it's going to be better than, most people at most things? You say that people are great generalists but what if there going to be a specialised "conductor" AI that is super-human at establishing communication between specialised AIs and dividing tasks super-humanly efficiently between them?

So when to start worrying?